Phase detector system

Abstract

A phase detection system ( 100 ) comprises an input terminal ( 101 ), first and second peak detectors ( 103, 113 ), an averaging unit ( 107 ), an offset unit ( 122 ), and a comparator ( 126 ). Input terminal ( 101 ) is coupled to the first and to the second peak detectors ( 103, 113 ) and provides an input signal to phase detection system ( 100 ). Averaging unit ( 107 ) is coupled between offset unit ( 122 ) and both the first peak detector and the second peak detector ( 103, 113 ), and generates an intermediate signal. Offset unit ( 122 ) is coupled to input terminal ( 101 ) and generates two comparable signals by applying a predetermined offset in signal strength to the input signal or the intermediate signal. The comparator ( 126 ) is coupled to the offset unit ( 122 ) and generates an output signal by comparing the two comparable signals which is indicative of the phase of the input signal.

1. A phase detection system comprising:
 an input terminal; 
 a first peak detection unit; 
 a second peak detection unit; 
 an averaging unit; 
 an offset unit; and 
 a comparator unit, 
 wherein the input terminal is connected to the first peak detection unit and to the second peak detection unit and wherein the input terminal provides an input signal to the phase detection system; 
 wherein the averaging unit is connected between the first peak detection unit and the offset unit and between the second peak detection unit and the offset unit, and wherein the averaging unit generates an intermediate signal; 
 wherein the offset unit is further connected to the input terminal and generates two comparable signals by applying a predetermined offset in signal strength to at least one signal of the group consisting of the input signal and the intermediate signal; and 
 wherein the comparator unit is connected to the offset unit and generates an output signal which is indicative of the phase of the input signal by comparing the two comparable signals, and wherein the phase detection system generates a first preliminary edge signal when the input signal equals the intermediate signal, and wherein the phase detection system generates a second edge signal when the intermediate signal equals zero. 
 
     
     
       2. The phase detection system of  claim 1 , wherein the first peak detector is a maximum peak detector. 
     
     
       3. The phase detection system of  claim 1 , wherein the second peak detector is a minimum peak detector. 
     
     
       4. The phase detection system according to  claim 1 , wherein the system further comprises a state machine. 
     
     
       5. The phase detection system according to  claim 4 , wherein the state machine is connected to at least one unit of the group consisting of the first peak detection unit, the second peak detection unit, the averaging unit and the offset unit. 
     
     
       6. The phase detection system according to  claim 4 , wherein the state machine generates a state signal that determines which signals are applied to the comparator unit and/or which peak detector unit is used to take a sample of the input signal. 
     
     
       7. The phase detection system according to  claim 6 , wherein the state machine switches between different states until a predetermined condition is met. 
     
     
       8. The phase detection system according to  claim 7 , wherein the predetermined condition is that the output signal of the comparator uniquely characterises the phase of the input signal. 
     
     
       9. The phase detection system according to  claim 8 , wherein the averaging unit generates an arithmetic mean of a signal of the first peak detection unit and a signal of the second peak detection unit. 
     
     
       10. The phase detection system according to  claim 9 , wherein the predetermined offset is set to be smaller than an amplitude of the input signal. 
     
     
       11. The phase detection system according to  claim 10 , wherein the predetermined offset is set to be greater than noise of the input signal. 
     
     
       12. The phase detection system according to  claim 1 , wherein the offset unit comprises a voltage source and/or a current source combined with a defined impedance. 
     
     
       13. A method for detecting a phase of an input signal, the method comprising:
 generating a first sampled signal by sampling the input signal with a first peak detection unit; 
 generating a second sampled signal by sampling the input signal with a second peak detection unit; 
 generating an intermediate signal out of the first sampled signal and the second sampled signal; and 
 generating an output signal by comparing the intermediate signal and the input signal in a comparator unit, wherein prior to the comparing a predetermined offset is applied to at least one of the intermediate signal and the input signal and wherein the output signal is indicative of the phase of the input signal. 
 
     
     
       14. The method according  claim 13  further comprising: providing a first state signal which first state signal triggers the generating of the first sampled signal. 
     
     
       15. The method according  claim 13  further comprising:
 providing a second state signal which second state signal triggers the generating of the second sampled signal. 
 
     
     
       16. The method according to  claim 13  further comprising:
 providing a third state signal which third state signal effects that the predetermined offset is positive. 
 
     
     
       17. The method according  claim 16  further comprising:
 alternately providing the third state signal and the fourth state signal until a predetermined condition is met. 
 
     
     
       18. The method according to  claim 13  further comprising:
 providing a fourth state signal which fourth state signal effects that the predetermined offset is negative.